1. Field of the Invention
The present invention relates to surgical instruments known as trocars which are used in endoscopic surgery to pierce or puncture an anatomical cavity to provide communication with the cavity during a surgical procedure. More particularly, the present invention relates to an improved tip for the obturator of the trocar.
2. Description of the Prior Art
Endoscopic surgery constitutes a significant method of performing surgeries and has become the surgical procedure of choice, because of its patient care advantages over xe2x80x9copen surgery.xe2x80x9d One form of endoscopic surgery is laparoscopic surgery, and a significant advantage of laparoscopic surgery over open surgery is the decreased post-operative recovery time. In most instances, a patient is able to leave the hospital within hours after laparoscopic surgery has been performed, whereas multi-day hospitalization is necessary to recover from open surgical procedures. Further, laparoscopic surgery provides decreased incidents of post-operative abdominal adhesions and decreased post-operative pain. Cosmetic results are also enhanced with laparoscopic surgery.
Conventionally, a laparoscopic surgical procedure begins with the insufflation of the abdominal cavity with carbon dioxide. The introduction of this gas into the abdominal cavity lifts the abdominal wall away from the internal viscera. The abdominal wall is then penetrated with a device known as a trocar, which includes a body assembly, a cannula assembly attached to the body assembly to form a bore through the body assembly, and a pointed element called an obturator. The obturator slides in the bore of the trocar and has a piercing tip at its end. After insertion of the trocar through the abdominal wall of the patient, the obturator is removed by the surgeon while leaving the cannula or tube protruding through the body wall. Laparoscopic instruments can then be inserted through the cannula to view internal organs and to perform surgical procedures.
The tip of the obturator of a trocar has traditionally employed a sharp cutting blade to assist the surgeon in penetrating the abdominal wall. However, certain trocars, for example, as disclosed in U.S. Pat. No. 5,817,601 to Goodwin, have employed a pair of blunt-edged blades or tissue separators which are located on the tip of the trocar to facilitate the penetration or dissection of tissue.
The trocar assembly disclosed in U.S. Pat. No. 5,817,061 to Goodwin and U.S. Pat. No. 5,591,192 to Privitera are manufactured and sold by Ethicon Endo-Surgery, Inc. Trocars as described in the ""061 and ""192 patents have at the time of filing this application been recalled by Ethicon since the tip of the obturator has been prone to failure. In particular, the tip of the trocars disclosed in the ""061 and ""192 patents have experienced incidents of snapping off during the insertion of the trocar. It is believed that this failure may be attributable to the blunt shape of the tip and the forces to which the tip is subjected upon insertion.
In accordance with the present invention, a trocar is provided which comprises a body assembly and a cannula assembly which is attached to the body assembly to define a bore therethrough. A trocar in accordance with the present invention also includes an obturator assembly for sliding engagement in the bore. The obturator assembly comprises a shaft having a longitudinal axis and having a distal end for insertion into the body of a patient. The distal end of the obturator includes a tip which is non-conical and which has upper and lower faces which taper away from the shaft to form a V-shaped distal end of the tip. Wing elements are provided between the upper and lower faces proximate the distal end of the obturator. The wing elements are spaced approximately 180 degrees from one another, and the wing elements may be blunt or they may have sharp cutting edges.
A trocar in accordance with the present invention may further comprise dorsal elements on the upper and lower faces. These dorsal elements also facilitate the insertion of the trocar.
By using the foregoing design for the tip of the obturator, the penetration forces associated with insertion of the trocar into a patient are directed away from the tip of the obturator. Also, less insertion force being required to insert a trocar of the present invention as compared to the force required to insert existing blunt tip trocars. The wing and dorsal elements also widen and dilate the wound track to ease entry of the trocar into the wound area.
In a preferred embodiment of the present invention, the obturator tip is releaseably engaged with the shaft of obturator, so that the same trocar may be used with either blunt wing elements or wing elements having sharp cutting edges.